Principle:Truera Trulens Session Initialization
| Knowledge Sources | |
|---|---|
| Domains | Observability, LLM_Evaluation |
| Last Updated | 2026-02-14 08:00 GMT |
Overview
A session management pattern that establishes and configures a centralized observability session for LLM application evaluation and tracing.
Description
Session Initialization is the foundational step in any LLM observability pipeline. It establishes a singleton session object that manages database connections, evaluation orchestration, and OpenTelemetry tracing configuration. The session serves as the central coordination point for all subsequent instrumentation, recording, and evaluation activities. Without an initialized session, no traces can be stored and no feedback evaluations can be persisted.
The pattern addresses the need for a single, consistent entry point that handles:
- Database backend selection (SQLite, PostgreSQL, Snowflake)
- Evaluator lifecycle management for deferred feedback execution
- OpenTelemetry tracer provider configuration
- Experimental feature flag management
Usage
Use this principle at the very beginning of any TruLens-based evaluation pipeline. It must be the first step before any application wrapping, feedback configuration, or recording. The session must be initialized once per process and is typically configured with a database connector appropriate for the deployment environment (local SQLite for development, Snowflake for production).
Theoretical Basis
Session Initialization follows the Singleton design pattern, ensuring exactly one session instance exists per process. This is critical for observability systems where:
- All traces must be routed to a single database backend
- Evaluator threads must be coordinated centrally
- OpenTelemetry tracer providers must be configured once globally
The pattern also implements Dependency Injection for the database connector, allowing the same evaluation code to target different storage backends without modification.
Pseudo-code Logic:
# Abstract session initialization pattern
session = create_singleton_session(
connector=select_database_backend(),
feature_flags=configure_experimental_features()
)
# Session now manages: database, evaluators, OTEL tracing